GHSA-9g9w-hmvj-5h57 is a high-severity (CVSS 8.8) CWE-471 vulnerability in merge-deep. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-9g9w-hmvj-5h57 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Prototype Pollution in merge-deep
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
merge-deepnpmDescription
Versions of merge-deep before 3.0.1 are vulnerable to prototype pollution via merging functions.
Recommendation
Update to version 3.0.1 or later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | merge-deep | all versions | 3.0.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for merge-deep. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update merge-deep to 3.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9g9w-hmvj-5h57 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-9g9w-hmvj-5h57 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-9g9w-hmvj-5h57. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-9g9w-hmvj-5h57 in your dependencies?
O3 detects GHSA-9g9w-hmvj-5h57 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.